This project is concerned with the finding out of the role of the endocrine system in the onset and progress of cancer, particularly of the breast and prostate, in man. The entire interconnected endocrine system is the target of the study with special emphasis on gonadal, pituitary and adrenal hormones. Every facet of the physiology and biochemistry of these hormones, both qualitative and quantitative, is studied in cancer patients and in controls to detect any possible differences which are either the result of, or the cause of the disease. Animal and in vitro studies are also employed to elicit information about the behavior of these hormones under circumstances where human studies are not possible. Because we are interested in measuring the principal hormones and also most if not all of their metabolites including the so called minor ones, we will devote much attention to the development of methods of measurements not only of the substances themselves but also of the reactions involved in their genesis. The participation of receptors in the expression of the biological action of these hormones requires methodology for the measurement and characterization of these substances and work on new methods to achieve these aims will be carried out. BIBLIOGRAPHIC REFERENCES: Fishman, J., Fishman, J.H., Nisselbaum, J.S., Menendez-Botet, C., Schwartz, M.K., Martucci, C., and Hellman, L. Measurement of the Estradiol Receptor in Human Breast Tissue by the Immobilized Antibody Method. J. Clin. Endo. and Metab. 40: 724, 1975. Tulchinsky, D., Frigoletto, F.D. Jr., Ryan, K.J., and Fishman, J. Plasma Estetrol as an Index of Fetal Well-being. J. Clin. Endo. and Metab. 40:560, 1975.